It is now known that certain eutectic alloys respond to proper directional solidification conditions to produce useful microstructures in which the second phase is aligned. This is generally described in the patent to Kraft, U.S. Pat. No. 3,124,452. The patent to Thompson and Lemkey, U.S. Pat. No. 3,564,940, describes a class of compositions which solidify according to the monovariant eutectic reaction to provide aligned poly phase structures. In U.S. Pat. No. 3,671,223, the concept has been further developed to include those systems which solidify according to the multivariant eutectic reaction.
U.S. Pat. No. 3,671,223 describes certain eutectic compositions which can be directionally solidified to produce M.sub.7 C.sub.3 type fibers in an iron, cobalt, or nickel matrix. U.S. Pats. Nos. 3,554,817, 3,793,010 and 4,111,723 describes more specific nickel base eutectic compositions for use at elevated temperatures.